DC-DC converters generally use different control mechanisms for adjusting and stabilizing their output voltage and output current. In order to maintain a constant output voltage level, a DC-DC converter draws current from an input power in order to meet what is required by the load. The maximum output current is limited by a current control mechanism. The current control mechanism typically senses the output current, converts the sensed magnitude into a corresponding voltage level and compares this voltage level with a given reference voltage level. The reference voltage level defines the upper and/or lower limit for the output current. However, the current drawn from the input power supply can cause a significant voltage drop across the output impedance of the input power supply. This can adversely affect the available input voltage level for the DC-DC conversion. Conventionally, this is prevented by setting an upper limit for the output current of the DC-DC converter including a safety margin for power supplies having relatively large output impedances. However, even then, the output impedance of the input power supply may exceed any maximum values and the input voltage level may drop below a minimum. This usually triggers an under-voltage lockout mechanism and the DC-DC converter is turned off.